1. Field of the Invention
This invention relates to an 80% VOC (Volatile Organic Compound), single phase aerosol hair spray composition, and, more particularly, to a hair spray composition based upon greater than 15% hydrocarbon as propellant having advantageous spray characteristics and acceptable user performance.
2. Description of the Prior Art
Aerosol hair sprays based on alcohol as the solvent for a hair fixative resin have employed hydrocarbons such as propane and butane as the propellant. Hydrocarbons are useful in such compositions because they are low cost and also because they can be used in economical unlined tin plate cans. However, recent governmental legislation has required that hair sprays contain less ethanol and/or propellant, which are the volatile organic constituents in the composition. For example, to meet an 80% VOC standard, it is necessary that the ethanol and propellant components comprise no more than 80% by weight of the composition. However, hydrocarbons are less soluble in such a high water content composition; in fact, in a water-hydrocarbon system containing more than 15% hydrocarbon, the composition separates into 2 phases, an aqueous phase and a hydrocarbon phase. Furthermore, the increased water content in the composition may cause can corrosion problems. For these reasons, dimethyl ether has been suggested as a replacement for hydrocarbon propellants. Dimethyl ether is advantageous as a propellant because it is soluble up to 35% in water. However, dimethyl ether is costly and also it does not alleviate the potential problem with can corrosion. In fact, DME may dissolve the rubber gasketing present in the valve of the actuator mechanism.
The state of the prior art in this field is represented by the following patents:
Martino, in U.S. Pat. No. 5,021,238, described a 2-phase aerosol hair spray composition having a dimethyl ether-to-water weight ratio of greater than 0.5:1. This composition, however, required shaking before use to form a semi-stable emulsion.
Shepard, in U.S. Pat. No. 3,137,416, described a 3-phase aerosol system for dispensing a hair spray resin comprising a gaseous propellant, a liquid propellant and an aqueous liquid.
Presant, in U.S. Pat. No. 3,207,386 described a 2-phase system for dispensing a liquid from a container under pressure by means of vaporization of a propellant within the container. The system comprised a propellant as the vapor phase and an essentially continuous liquid as the aqueous phase, and further included an active ingredient as solute, water as solvent and dimethyl ether as propellant. No hydrocarbon propellants were present, however, in this system.
Clapp, in U.S. Pat. No. 2,995,278, described a package for dispensing an aerosol spray composition which was present in the form of both aqueous and non-aqueous phases. The non-aqueous phase included both a hydrocarbon and a liquified halogen-substituted hydrocarbon as propellants. Dimethyl ether was not present in this composition.
Other patents in this field include U.S. Pat. Nos. 4,134,968; 4,874,604; 4,933,170; 5,176,898; 4,923,695; 4,315,910; and 5,266,303.
Accordingly, it is an object of this invention to provide an 80% VOC, single phase aerosol hair spray composition based upon an amount greater than 15% of hydrocarbon as the propellant.
Another object of this invention is to provide an 80% VOC, single phase aerosol hair spray composition having 15.1 to 20% hydrocarbon as propellant and 0.5 to 5% dimethyl ether as solubilizer for all the components of the composition.
Still another object herein is to provide such a hair spray composition having advantageous spray patterns and user performance.
These and other objects and features of the invention will be made apparent from the following description of the invention.